There are some societies of religious life whose members never make perpetual vows; it is possible for a woman to leave such a society and retire to wherever (though she'd have to pay for it somehow). But for members of orders who make perpetual vows, such a thing is generally not possible.

The religious life is not a job or occupation but a vocation. It is not what she does but who she is. If the religious was in an active apostolate (e.g., teaching) she may retire from that work when she gets older, but she would not retire from being a religious.

Religious, whether Nuns, Brothers or Priests, are the responsibility of their community (the specific Order, and Congregation that they belong to). They all take a vow of poverty, which means that everything is owned by the community, and NOT by any individual.

The community (such as "The Dominican Sisters of Mission San Jose" as just one example) is responsible for their care throughout their life. Generally, they do whatever work they can, for as long as they possibly can, even in "retirement". Their medical expenses, etc. are all borne by their community, and when they die, they are normally buried in their community cemetery.

This is not just a "Job". This is their life, 24/7, forever, once they have taken their final vows. The Nun who converted me, by her example of just living a happy life, was still teaching at the College level, when she suffered her fatal accident at the age of 85 plus.

I knew a 'sister Paulinus', a teacher-nun in Apeldoorn who after she retired as a teacher, also left her order (Franciscan I think) and lived in a little apartment next to the church for the rest of her life, using her normal name. She was quite well-known in Apeldoorn, my mom was taught by her, and all my aunts and my uncle. But yes...that's very rare!

The religious life is not a job or occupation but a vocation. It is not what she does but who she is. If the religious was in an active apostolate (e.g., teaching) she may retire from that work when she gets older, but she would not retire from being a religious.